Families of Chefland

Chefland is inhabited by chefs, which have only one gender. Each chef can, alone, give birth to many younger chefs, which can then give birth to even younger chefs, and so on. It is easy to see that the family structure of any chef (formed by this chef's direct and indirect descendants) is a tree. A *family* is a tree such that its root does not have a parent, i.e. it is not a proper subtree of a